/Engine/Source/Runtime/Engine/Classes/GameFramework/AsyncActionHandleSaveGame.h
Schedule an async save to a specific slot.UGameplayStatics::AsyncSaveGameToSlotis the native version of this. When the save has succeeded or failed, the completed pin is activated with success/failure and the save game object. Keep in mind that some platforms may not support trying to load and save at the same time.
static [UAsyncActionHandleSaveGame](API\Runtime\Engine\GameFramework\UAsyncActionHandleSaveGame) * AsyncSaveGameToSlot ( [UObject](API\Runtime\CoreUObject\UObject\UObject) * WorldContextObject, [USaveGame](API\Runtime\Engine\GameFramework\USaveGame) * SaveGameObject, const [FString](API\Runtime\Core\Containers\FString) & SlotName, const int32 UserIndex )